A wide variety of tools are commonly used in the oil and gas industry for forming wellbores, in completing wellbores that have been drilled, and in producing hydrocarbons such as oil and gas from completed wells. Examples of such tools include cutting tools, such as drill bits, reamers, stabilizers, and coring bits; drilling tools, such as rotary steerable devices and mud motors; and other downhole tools, such as window mills, packers, tool joints, and other wear-prone tools. These tools, and several other types of tools outside the realm of the oil and gas industry, are often formed as metal matrix composites (MMCs), and referred to herein as “MMC tools.”
An MMC tool is typically manufactured by placing loose powder reinforcing material into a mold and infiltrating the powder material with a binder material, such as a metallic alloy. The various features of the resulting MMC tool may be provided by shaping the mold cavity and/or by positioning temporary displacement materials within interior portions of the mold cavity. A quantity of the reinforcement material may then be placed within the mold cavity with a quantity of the binder material. The mold is then placed within a furnace and the temperature of the mold is increased to a desired temperature to allow the binder (e.g., metallic alloy) to liquefy and infiltrate the matrix reinforcement material.
MMC tools are generally erosion-resistant and exhibit high impact strength. The outer surfaces of MMC tools are commonly required to operate in extreme conditions. As a result, it may prove advantageous to customize the material properties of the outer surfaces of MMC tools to extend the operating life of a given MMC tool.